In many lossy compression schemes of audio and video, the strength of the compression can be selected to achieve a compression level that is perceptually acceptable to the human visual system (HVS). Because the human visual system is complex, it is difficult to select an optimal compression level. On one hand, it is desirable to compress an image into a relatively small number of bits, thus reducing the bandwidth required to transmit the image. On the other hand, some compression schemes can result in a reduced image quality as perceived by the HVS if the image is compressed at too high a compression ratio.